BLDC Motor Noise Issue During Six-Step Commutation

[PANDI902]

Hi Team,

I am currently working on a 48V HALL sensored based BLDC motor control system (three-phase) using the STM32F405RGT6, DRV8300, and STP100N10F7 MOSFETs. The motor is running using six-step commutation PWM.

Although the motor is rotating, I am experiencing significant noise during operation. I have tested PWM frequencies ranging from 12 kHz to 20 kHz and am currently using a dead time of 1.25 µs.

Under no-load conditions, the phase outputs (U, V, and W) appear correct. However, when the motor is connected, the waveforms on all three phases become distorted and are not as expected.

I have attached the output video and image for reference. Could you please suggest possible solutions to reduce the noise and improve the waveform quality? Any guidance, tuning recommendations, or reference code would be greatly appreciated.

Regards,
Veerapandiyan V.
1.With_Out_Load_ON_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)

Without_LOad_On

2.With_Out_Load_Off_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)

Without_LOad_Off

3.With_Out_Load_MOSFET_WaveForm_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)

4.With_Load_MOSFET_WaveForm_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)_1

With_Load_1

5.With_Load_MOSFET_WaveForm_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)_2

With_Load_2

6.With_Load_MOSFET_WaveForm_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)_3

With_Load_3

7.With_Load_MOSFET_WaveForm_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)_4

With_Load_4

8.With_Load_MOSFET_WaveForm_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)_5

With_Load_5

9.With_Load_MOSFET_WaveForm_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)_6

With_Load_6

10.With_Load_MOSFET_WaveForm_On_Off_PHASEA_HIGH_SIDE(yELLOW_lOW_SIDE_Blue)_7

With_Load_On_Off

11.3.3Volt_Power_Li

3.3V_Power_Line_Switching_Time

[Fabrice LOUBEYRE]

Hi @PANDI902, I suggest checking the PWM outputs of the STM32F405RGT6. If the PWM signals are clean under load before the driver, the problem is likely located on the power side, specifically the driver and MOSFETs.

Best regards.

Fabrice

[PANDI902]

Hi Fabrice,

Thank you for your suggestion.

I have uploaded the BLDC driver power board schematic. Could you please review it and share your feedback?

I have also attached the waveform measurements for both no-load and load conditions for your reference previous Chat eleven Images.

Regards,
Veerapandiyan V.

[PANDI902]

Hi Fabrice,

Any Update. I am waiting for your reply.

Regards,
Veerapandiyan V.

[GMA]

Hello @PANDI902,

As noted by Fabrice, are the PWM outputs of the STM32F405RGT6 correct?
Are you using the ST MCSDK Suite (as the STM32F405RGT6 does not belong to the STM32 supported family)?